Boron is one of seven micronutrients essential to all plant growth. Its role was recognised first in the 1920s
and since that time, boron deficiency has been recognised in a wide range of crops.
Correcting boron deficiency
Boron deficiency can be remedied by the correct application of a borate containing material in solid or
liquid fertilisers, to the seedbed in annual crops or under the foliar canopy of perennial crops. Perennial and
annual crops can also be sprayed with boron containing solutions. These are normally tank mixed with other
micronutrients or with agrochemical products.
The latter method of application may be preferable since at peak requirement times the boron needs of
the growing plant can frequently exceed its ability to obtain its needs through the roots. Mixing with other
sprays as part of a programme enables the grower to time this availability and save application cost.
Detecting boron deficiency
Boron deficiency shows in clearly defined ways in certain crops. Generally, by the time visible symptoms are
seen, yields will already have been adversely affected. The best way to establish need is either through soil
testing or through tissue analysis. In this way, boron supplementation can form part of a ‘balanced nutrition’
approach to crop fertilisation.
Predicting boron deficiency
Certain crops world-wide are known to be more susceptible to lack of boron than others.
There are several factors which need to be taken into account when boron deficiency may be suspected:
• High rainfall
• Recent liming (pH over 6.6)
• Previous cropping
• Boron removal by previous crops
• No boron nutrition
• Sandy soils
• High organic matter
Mineral Nutrition of Higher Plants, by Horst Marschner, Academic Press.
Boron and its Role in Crop Production, by Umesh C. Gupta. CRC Press.